Railway Upgrades for Rural American Lines Act or the RURAL Act This bill modifies requirements for the Railway-Highway Crossings Program. Specifically, the bill (1) requires the Department of Transportation to set aside highway safety improvement funds for states for the replacement of functionally obsolete warning devices at railway-highway crossings, (2) increases the federal share payable on account of any project financed with highway safety improvement funds from 90% to 100%, and (3) revises the amount of incentive payment a state may provide a local government for permanent closure by such government of public at-grade railway-highway crossings.